'''
斐波那契数就是当前项的值等于前两项的和
1 2 3 4 5 6 7
0 1 1 2 3 5 8...
'''



def fit(n):
    first_num = 0
    second_num = 1

    if n == 1:
        num = first_num

    if n == 2:
        num = second_num

    if n > 2:
        num = fit(n-2) + fit(n-1)

    print(f'当前的斐波那契数是：{num}')

n = int(input('请输入你想知道的序号的斐波那契数：'))

fit(n)